private void fireImageBoxEventInternal(ImageFieldEvent e) {
   EventListener[] a = m_listenerList.getListeners(ImageFieldListener.class);
   if (a != null) {
     for (int i = 0; i < a.length; i++) {
       ((ImageFieldListener) a[i]).imageFieldChanged(e);
     }
   }
 }
 @Override
 public void removeImageFieldListener(ImageFieldListener listener) {
   m_listenerList.remove(ImageFieldListener.class, listener);
 }
 /** model observer */
 @Override
 public void addImageFieldListener(ImageFieldListener listener) {
   m_listenerList.add(ImageFieldListener.class, listener);
 }